The present invention is related to configuring equipment in a communication system and in particular to providing desired pin or cable connections for full duplex network data communications.
Equipment in a data communication or network system is typically connected by using cables, fiber optics and the like, to establish serial data communication links between the equipment. A number of different standards for connectors, cabling and the like have been used or proposed, including, for example, 10 base-T systems, T1 systems, RS-232 systems, and other systems and links.
At least some systems can be configured for full duplex communication allowing communications which are outbound (with respect to particular equipment in the system) to occur simultaneously with communications which are in-bound. Typically, this means that the equipment will be provided with separate connector pins for out-bound (transmitter or TX) signals and for in-bound (receiver or RX) signals. In at least some systems, equipment is provided in which a set of pins to be used for RX and TX signals can be configured (e.g. manually configured by the user) in either of two configurations. For example, in certain RS-232 systems equipment may be configured by the user as data communication equipment (DCE) in which a first pin or set of pins (e.g. pin 2) is provided as a TX pin and another pin or set of pins (e.g. Pin 3) is established as the RX pin. Alternatively, the user may manually configure the equipment as data terminal equipment (DTE) with the opposite configuration, e.g. in which pin 2 is the RX pin and pin 3 is the TX pin. Typically, which configuration should be used (i.e. DCE or DTE) depends upon the configuration of the other equipment to which a device is connected. In general, connected devices should have opposite configurations such that equipment which is connected to DCE should be configured as DTE and equipment which is connected to DTE should be configured as DCE.
In many situations, the configuration choices for end users can be confusing and/or time-consumptive and expensive. End users may not know how a particular piece of equipment should be configured for proper operation. This may require a time-consumptive trial-and-error procedure for setting up a communication system or network, which can be relatively expensive, especially when a system contains multiple terminals or nodes. Accordingly, it would be useful to provide a system which can achieve substantially automatic configuration for establishing a full duplex data link, i.e., without the need for manual switching between potential configurations or other similar trial-and-error techniques, especially without the need for a human user to select or implement a choice among two or more possible configurations. Preferably, the automatic configuration system can be implemented in a fashion which is relatively easy to design, fabricate, maintain and/or repair and which is relatively inexpensive, especially in terms of a price to an end user, for the equipment.
The present invention includes a recognition of the existence, nature and/or source of the problems in previous approaches, including as described herein. In one aspect, the communication equipment or terminal equipment is provided with an electrically controllable switch, for changing between two or more configurations (e.g. changing between DTE and DCE configurations) and a control device which receives signals indicative of whether a desired communication link has been established, and which toggles the switch, among the possible configurations, until such time as a desired link is detected. In one embodiment, the control circuitry includes circuitry which is already present in the communication device for other purposes, such as a microprocessor. Thus, in one aspect the invention can be implemented by, among other things, providing programming to a microprocessor so as to control a switch and/or to recognize the existence of a desired communication link.
In various aspects, the switch may comprise a electromagnetic actuator, i.e. a relay, or the switch may comprise a plurality of switchable amplifiers, i.e. an electronic switch.
In one aspect one or more nodes of a data communication system is automatically switched between two or more possible node configurations, such as between a DTE configuration and a DCE configuration, until the presence of a carrier (or actual data) or similar indicator signal is sensed. Configuration devices include relays and electronic switches. Control devices preferably are microprocessor based. In one aspect, upon power up or other initiation, the microprocessor toggles an output control signal so as to repeatedly toggle a switch between, e.g., DTE and DCE positions and to terminate the toggling when a link indicator is detected. In some embodiments, if desired control devices and/or switching devices can be integrated together with other functions, e.g. a modulator/demodulator in an Ethernet transceiver.